“I thought the situation was that Gov. Blagojevich got a huge campaign contribution from the union, and virtually as soon as he got into office he took out his pen and signed an executive order that had the effect of putting, what was it, $3.6 million into the union coffers?”

But Illinois Attorney Lisa Madigan, whose office argued the case against Harris, said the state does havea compelling interest in promoting union representation of these workers.

SUPREME FIGHTER: Pam Harris and her son Josh.

“What the State of Illinois has had to do, as you heard during the argument, is find a mix of benefits so we’re able to attract and retain a high-quality workforce,” she said. “And quite frankly, before there was an exclusive representative engaged in collective bargaining, that was not the case in Illinois.”

Between 2002 and 2012 Madigan received $779,773 in campaign donations from government worker unions, including $129,000 from the SEIU.

The court’s four more liberal justices appeared to oppose changing the law.

In fact, Justice Stephen Breyer said if the court were to do so it would overturn 35 years of established legal precedent.

On the other hand, some of the more conservative members of the court – Chief Justice John Roberts, Alito and Justice Anthony Kennedy appeared ready to side with Harris and the others who brought the lawsuit. Justice Clarence Thomas did not ask questions during oral arguments, which is his practice.

That leaves Scalia, usually a stalwart conservative, as the potential swing vote on what seems to be a case centered on freedom of speech.

Workers who refuse to join a union are often charged a “representation fee,” which is supposed to cover the cost of things like collective bargaining but not union political activities.

Kennedy noted that defining what is and isn’t political activity is difficult. For example, he said collective bargaining for government workers affects the size of government — something that has political implications “in an era where government is getting bigger and bigger, and this is becoming more and more of an important issue to more people.”

If the court finds in Harris’ favor, public-sector labor unions could be weakened, Harvard Law School Professor Benjamin Sachs, an expert on labor law and a former SEIU attorney, told INN in an interview last week.

If the court issues a narrow ruling, it could say that home care workers are not state workers and can’t be compelled to give money to a union. This would deprive unions of a significant amount of revenue that they are now receiving.

In fact, some justices expressed skepticism about whether these workers, many of whom are caring for relatives, really meet the definition of state employees.

Alito noted that if a home care worker were to make a mistake resulting in a patient’s death the state would not be liable because in that context the workers are not considered state employees.

But the high court also could hand down a broader ruling that could have an even greater impact on public-sector unions, Sachs said.

In such a ruling, the high court would rule that government workers cannot be compelled to give money to a union based on First Amendment grounds.

The attorneys representing Harris contend her right to free speech is being infringed upon because she is being compelled by government to pay a union to advocate a point of view in collective bargaining that she may not agree with.

Sachs said unions fear the justices will buy into this argument because some workers may decide not to contribute to the union but still could benefit from the union’s collective bargaining activities.

“In right-to-work states, you have more ‘free riders,’ and unions there are not as strong,” he said.

Scalia asked several questions and made statements sympathetic to the union.

In summing up the Supreme Court’s past rulings, he said, “You can be compelled not to be a free rider, to pay for those items of bargaining that benefit you as well as everybody else.”

The Supreme Court is expected to rule on the case this summer.

Harris, for her part, doesn’t see herself as a potential “free rider.” In fact, she doesn’t consider herself a state employee, adding she is just a mother looking after her son.

“I’m only doing this because it’s the right thing for Josh. I didn’t want – I didn’t seek out – publicity or to become the face of changing public-sector unions. I just really wanted to do what was right for Josh.”

Scott Reeder is a veteran statehouse reporter and the journalist in residence at the Illinois Policy Institute. He can be reached at sreeder@illinoispolicy.org. Readers can subscribe to his free political newsletter by going to ILNEWS.ORG or follow his work on Twitter @scottreeder